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RegenerationofLimbs Mostpeoplewouldagreethatitwouldbewonderfulifhumanscouldregeneratelimbs.Thosewhohavelosttheirarmsorlegswouldbecompleteagain.Thedayisstillfaroffwhenthismighthappen.Butinthelast10yearsdoctorshavereportedregenerationinsmallerpartsofthebodymostoftenfingers. Regenerationisnotanewly-discoveredprocess.Forcenturiesscientistshaveseenitworkinsomekindsofanimals.Breakoffalizards蜥蜴的tailforexampleanditwillgrowanewtail.Scientistsnowarelookingforawaytoturnonthisexcitingabilityinmorehighly-developedanimalsincludinghumans.Theirexperimentsshowthatnervescellchemistryandthenaturalelectriccurrentsinthebodyallseemtohaveapartinthisprocess. Thebodyofeveryanimalcontainsgeneralpurposecellsthatchangeintowhateverkindofcellsthebodyneeds.Animalssuchasthelizardorsalamander蝾螈usethesecellstoregenerateanewtailorlegwhentheoldoneisbrokenoff.Thesecellscollectaroundthewound.Theyformamasscalledablastema胚基.Thecellsoftheblastemabegintochange.Somebecomebonecellssomemusclecellssomeskincells.Slowlyanewpartre-growsfromthebodyoutward.Whencompletedthenewpartisjustliketheoldone. Morethan200yearsagoItalianscientistLuigiSpallanzanishowedthatyoungeranimalshaveagreaterabilitytoregeneratelostpartsthanolderanimals.Sodoanimalslowerontheladderofevolutionarydevelopment.Themajordifferenceseemstobethatless-developedanimalshavemorenervesintheirtailsandlegsthanhumansdointheirarmsandlegs. Anotherhelpfulpieceofinformationwasdiscoveredinthelate1800s.Scientistsfoundthatwhenacreatureisinjuredanelectricalcurrentflowsaroundthewound.Thestrengthofthecurrentdependsonhowseverethewoundisandonhowmuchnervetissueispresent. In1945AmericanscientistMerylRosetestedanotherideaaboutregeneration.Hethoughtanewlimbmightgrowonlyfromanopenwound.DoctorRosecutoffthefrontlegsofsomefrogsbelowtheknee.Hekeptthewoundswetwithastrongsaltyliquid.Thispreventedskinfromgrowingoverthewounds.Theresultsweresurprising.Frogsdonotregeneratenewlegsnaturally.Butthesefrogsbegantogrownewlimbs.Abouthalfofeachcut-offleggrewbackagain.Newbonesandmusclesdeveloped. Thisresearchhasleddoctorstonewwaysoftreatingcut-offfingers.Doctorshaveobservedforexamplethatmanychildrenandsomeadultswillre-growthetopofafingerifthewoundisleftopen. Regenerationofapartofthebodyisimpossiblewithout______.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
RegenerationofLimbs Mostpeoplewouldagreethatitwouldbewonderfulifhumanscouldregeneratelimbs.Thosewhohavelosttheirarmsorlegswouldbecompleteagain.Thedayisstillfaroffwhenthismighthappen.Butinthelast10yearsdoctorshavereportedregenerationinsmallerpartsofthebodymostoftenfingers. Regenerationisnotanewly-discoveredprocess.Forcenturiesscientistshaveseenitworkinsomekindsofanimals.Breakoffalizards蜥蜴的tailforexampleanditwillgrowanewtail.Scientistsnowarelookingforawaytoturnonthisexcitingabilityinmorehighly-developedanimalsincludinghumans.Theirexperimentsshowthatnervescellchemistryandthenaturalelectriccurrentsinthebodyallseemtohaveapartinthisprocess. Thebodyofeveryanimalcontainsgeneralpurposecellsthatchangeintowhateverkindofcellsthebodyneeds.Animalssuchasthelizardorsalamander蝾螈usethesecellstoregenerateanewtailorlegwhentheoldoneisbrokenoff.Thesecellscollectaroundthewound.Theyformamasscalledablastema胚基.Thecellsoftheblastemabegintochange.Somebecomebonecellssomemusclecellssomeskincells.Slowlyanewpartre-growsfromthebodyoutward.Whencompletedthenewpartisjustliketheoldone. Morethan200yearsagoItalianscientistLuigiSpallanzanishowedthatyoungeranimalshaveagreaterabilitytoregeneratelostpartsthanolderanimals.Sodoanimalslowerontheladderofevolutionarydevelopment.Themajordifferenceseemstobethatless-developedanimalshavemorenervesintheirtailsandlegsthanhumansdointheirarmsandlegs. Anotherhelpfulpieceofinformationwasdiscoveredinthelate1800s.Scientistsfoundthatwhenacreatureisinjuredanelectricalcurrentflowsaroundthewound.Thestrengthofthecurrentdependsonhowseverethewoundisandonhowmuchnervetissueispresent. In1945AmericanscientistMerylRosetestedanotherideaaboutregeneration.Hethoughtanewlimbmightgrowonlyfromanopenwound.DoctorRosecutoffthefrontlegsofsomefrogsbelowtheknee.Hekeptthewoundswetwithastrongsaltyliquid.Thispreventedskinfromgrowingoverthewounds.Theresultsweresurprising.Frogsdonotregeneratenewlegsnaturally.Butthesefrogsbegantogrownewlimbs.Abouthalfofeachcut-offleggrewbackagain.Newbonesandmusclesdeveloped. Thisresearchhasleddoctorstonewwaysoftreatingcut-offfingers.Doctorshaveobservedforexamplethatmanychildrenandsomeadultswillre-growthetopofafingerifthewoundisleftopen. Thepassageindicatesthat______.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. Interferonhasnotbeenwidelyusedbecauseitisstillverydangerous.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
Ifyouhaveany{{U}}complaint{{/U}}pleaseseethemanager.
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EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
Hissuccessinworkhastemptedmanytotrythisnewmethod.
OldMothers’ChildrenHaveHigherDiabetes糖尿病Risk Childrenofoldermothersrunahigherriskofdevelopinginsulin-dependent胰岛素依赖型的diabetestheBritishMedicalJournalsaid.Astrongassociationwasfoundbetweenincreasingmaternal母亲的ageatdeliveryandriskofinsulin-dependentdiabetesinthechild.RiskwashighestinfirstbornchildrenanddecreasedprogressivelywithhigherbirthorderProfessorEdwinGaleandcolleaguesatSouthmeadHospitalinBristolsaid.Diabetesisaseriousincurablelifelongdiseasecharacterized以......作为特性byallinabilitytocontroltheamountofsugarintheblood.Insulin-dependentdiabeteswhichmainlyaffectschildrenistreatedbyadministeringthehormoneinsulin.Galelookedinto1375familiesintheOxfordareawhereoneormorechildrenhaddiabetesandfoundthattheriskofachilddevelopinginsulin-dependentdiabetesincreasedby25percentforeachfive-yearbandofthemothersage. Theriskofdevelopingdiabeteswasalsolinkedtotheageofthefather.Foreveryfive-yearbandofthefather’’sagetheriskofthechilddevelopingdiabetesincreasedbyninepercent.Theriskofdiabeteswashigh?estamongthefirstbornchildrenofmotherswhostartedtheirfamilieslateandtheriskdecreasedbyabout15percentforeachsubsequentchildtheBMJsaid.Theolderthemothertheearlierthestartofinsulin-dependentdiabetesinthechild.Otherstudieshavealreadyshownthatchildrenborntooldermothersovertheageof35haveanincreasedriskofdiabetesbutthisstudyisthefirsttoestablishthatriskincreasescontinuouslyinrelationtoincreasingmaternalageDr.PollyBingleyofSouthmeadHospitaltoldReuters路透社.Thenewstudyisthefirsttoshowthatriskisrelatedtobirthorder. Thestudyalsopartlyexplainsincreasingdiabetes.Between1970and1996theproportionofchildrenborntomothersagedbetween30and34increasedto28percentfrom15percentandthiscouldaccountforrisingnumbersofchildhooddiabetespatientsthescientistssaidinthealarmingincreaseintherateofinsulin-dependentdiabetesamongchildreninrecentyears.Thisstudymaywellprovideacluetotheunderstandingofthisproblem.ItismostlikelythatthereareanumberoffactorstoexplaintheincreaseDiabetesUKsaid.Therearesome1.4milliondiagnoseddiabetessufferersinBritainthecharityDiabetesUKsaid.Ofthese1.4millionsufferersthereare20000peopleunderage20whosufferfrominsulin-dependentdiabetes. Whatkindofchildmaybeatthehighestriskofdevelopinginsulin-dependentdiabetes?
MemoryClass StanFieldknowswhatagecandotoaperson’’smemoryandhe’’snottakinganychanceswithhis.Hechooseshisfoodcarefullyandgetsplentyofexercise.Healsoavoidsstresscocacolaandcigarettesmoke. What’’smoreatbreakfasteachmorningthe69-year-oldchemicalengineerswallowsaplatefulofpillsinthehopeofboostinghisbrainpower. MichelleAmoveislessthanhalfField’’sagebutnolessconcernedabouthermemory.Whileworkingroundtheclocktofinishadegreeinfilmstudiesthe33-year-oldNewYorkerhadthealarmingsensationthatshehadstoppedretaininganything.Icouldn’’tevenremembernamesshesays.IthoughtOhnoI’’mover30.It’’salldownhillfromhere.BesidesloadinguponsupplementsAmovesignedupforamemoryenhancingcourseatNewYork’’sMountSianiMedicalCenter.Andwhenshegotthereshefoundherselfsurroundedbypeoplewhowerejustasworriedasshewas. FormillionsofAmericansandespeciallyforbabyboomers生育高峰出生的人thedemandsoftheInformationAgeconflictwithasenseofdecliningphysicalpower.Whenboomerswereintheir30sand40stheylaunchedthefitnessboomsaysCynthiaGreenthepsychologistwhoteachesMountSinai’’smemoryclass.Nowwehavethemental-fitnessboomMemoryistheboomers’’newlife-crisisissue.Andofcourseamajormarketingopportunity.ThedemandforbooksandseminarshasneverbeengreatersaysJackLannomalongtimememorytrainerwhoseweeklyTVshowMindUnlimitedgoesoutto33millionhomesontheChristianNetwork.Anxiousconsumersarerushingtobuydo-it-yourselfprogramsandsupplementmakersaretryingtoselleverythingbutsawdust木屑asabrainbooster. Butbeforeyougetoutyourcheckbookafewquestionsareinorder.Doeseverydayforgetfulnesssignaldecliningbrainfunction?Ismegamemory超级记忆arealisticgoalfornormalpeople?Andifyoucouldhaveaperfectmemorywouldyoureallywantit?Untilrecentlynoonecouldaddressthoseissueswithmuchauthoritybutourknowledgeofmemoryisexploding.Newtechniquesarerevealinghowdifferentpartsofthebraininteracttopreservemeaningfulexperiences.Biologistsaretryingtounderstandtheunderlying潜在的chemicalprocessesandneuroscientists神经系统科学家arediscoveringhowagestressandotherfactorscandisruptthem.Nooneisclosetofindingthesecrettoperfectrecallbutasyou’’llseethatmaybejustaswell. Manybaby-boomerslivingintheInformationAgefeelthat______.
Icanhardlybelieveitit's{{U}}amazing{{/U}}.
Itishisassumptionofafalsetheorythatmadehimpayahighprice.
MemoryClass StanFieldknowswhatagecandotoaperson’’smemoryandhe’’snottakinganychanceswithhis.Hechooseshisfoodcarefullyandgetsplentyofexercise.Healsoavoidsstresscocacolaandcigarettesmoke. What’’smoreatbreakfasteachmorningthe69-year-oldchemicalengineerswallowsaplatefulofpillsinthehopeofboostinghisbrainpower. MichelleAmoveislessthanhalfField’’sagebutnolessconcernedabouthermemory.Whileworkingroundtheclocktofinishadegreeinfilmstudiesthe33-year-oldNewYorkerhadthealarmingsensationthatshehadstoppedretaininganything.Icouldn’’tevenremembernamesshesays.IthoughtOhnoI’’mover30.It’’salldownhillfromhere.BesidesloadinguponsupplementsAmovesignedupforamemoryenhancingcourseatNewYork’’sMountSianiMedicalCenter.Andwhenshegotthereshefoundherselfsurroundedbypeoplewhowerejustasworriedasshewas. FormillionsofAmericansandespeciallyforbabyboomers生育高峰出生的人thedemandsoftheInformationAgeconflictwithasenseofdecliningphysicalpower.Whenboomerswereintheir30sand40stheylaunchedthefitnessboomsaysCynthiaGreenthepsychologistwhoteachesMountSinai’’smemoryclass.Nowwehavethemental-fitnessboomMemoryistheboomers’’newlife-crisisissue.Andofcourseamajormarketingopportunity.ThedemandforbooksandseminarshasneverbeengreatersaysJackLannomalongtimememorytrainerwhoseweeklyTVshowMindUnlimitedgoesoutto33millionhomesontheChristianNetwork.Anxiousconsumersarerushingtobuydo-it-yourselfprogramsandsupplementmakersaretryingtoselleverythingbutsawdust木屑asabrainbooster. Butbeforeyougetoutyourcheckbookafewquestionsareinorder.Doeseverydayforgetfulnesssignaldecliningbrainfunction?Ismegamemory超级记忆arealisticgoalfornormalpeople?Andifyoucouldhaveaperfectmemorywouldyoureallywantit?Untilrecentlynoonecouldaddressthoseissueswithmuchauthoritybutourknowledgeofmemoryisexploding.Newtechniquesarerevealinghowdifferentpartsofthebraininteracttopreservemeaningfulexperiences.Biologistsaretryingtounderstandtheunderlying潜在的chemicalprocessesandneuroscientists神经系统科学家arediscoveringhowagestressandotherfactorscandisruptthem.Nooneisclosetofindingthesecrettoperfectrecallbutasyou’’llseethatmaybejustaswell. WhatdoesStanFieldtakeatbreakfast?
Doyouneedanybodyto{{U}}assist{{/U}}youinyourwork?
Below600feetoceanwatersrangefrom{{U}}dimly{{/U}}littocompletelydark.
Heclaimedproudlythathewasthebestswimmerinhisschool.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
RegenerationofLimbs Mostpeoplewouldagreethatitwouldbewonderfulifhumanscouldregeneratelimbs.Thosewhohavelosttheirarmsorlegswouldbecompleteagain.Thedayisstillfaroffwhenthismighthappen.Butinthelast10yearsdoctorshavereportedregenerationinsmallerpartsofthebodymostoftenfingers. Regenerationisnotanewly-discoveredprocess.Forcenturiesscientistshaveseenitworkinsomekindsofanimals.Breakoffalizards蜥蜴的tailforexampleanditwillgrowanewtail.Scientistsnowarelookingforawaytoturnonthisexcitingabilityinmorehighly-developedanimalsincludinghumans.Theirexperimentsshowthatnervescellchemistryandthenaturalelectriccurrentsinthebodyallseemtohaveapartinthisprocess. Thebodyofeveryanimalcontainsgeneralpurposecellsthatchangeintowhateverkindofcellsthebodyneeds.Animalssuchasthelizardorsalamander蝾螈usethesecellstoregenerateanewtailorlegwhentheoldoneisbrokenoff.Thesecellscollectaroundthewound.Theyformamasscalledablastema胚基.Thecellsoftheblastemabegintochange.Somebecomebonecellssomemusclecellssomeskincells.Slowlyanewpartre-growsfromthebodyoutward.Whencompletedthenewpartisjustliketheoldone. Morethan200yearsagoItalianscientistLuigiSpallanzanishowedthatyoungeranimalshaveagreaterabilitytoregeneratelostpartsthanolderanimals.Sodoanimalslowerontheladderofevolutionarydevelopment.Themajordifferenceseemstobethatless-developedanimalshavemorenervesintheirtailsandlegsthanhumansdointheirarmsandlegs. Anotherhelpfulpieceofinformationwasdiscoveredinthelate1800s.Scientistsfoundthatwhenacreatureisinjuredanelectricalcurrentflowsaroundthewound.Thestrengthofthecurrentdependsonhowseverethewoundisandonhowmuchnervetissueispresent. In1945AmericanscientistMerylRosetestedanotherideaaboutregeneration.Hethoughtanewlimbmightgrowonlyfromanopenwound.DoctorRosecutoffthefrontlegsofsomefrogsbelowtheknee.Hekeptthewoundswetwithastrongsaltyliquid.Thispreventedskinfromgrowingoverthewounds.Theresultsweresurprising.Frogsdonotregeneratenewlegsnaturally.Butthesefrogsbegantogrownewlimbs.Abouthalfofeachcut-offleggrewbackagain.Newbonesandmusclesdeveloped. Thisresearchhasleddoctorstonewwaysoftreatingcut-offfingers.Doctorshaveobservedforexamplethatmanychildrenandsomeadultswillre-growthetopofafingerifthewoundisleftopen. InDr.Rose’stestfrogswithcut-offlegs______.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
Theoldconcernsloseimportanceandsomeofthem{{U}}vanish{{/U}}altogether.
Attheconferencethespeakertriedtoexpresshisfeelingsconcerningtheurgencyoffavorabledecisions.
OldMothers’ChildrenHaveHigherDiabetes糖尿病Risk Childrenofoldermothersrunahigherriskofdevelopinginsulin-dependent胰岛素依赖型的diabetestheBritishMedicalJournalsaid.Astrongassociationwasfoundbetweenincreasingmaternal母亲的ageatdeliveryandriskofinsulin-dependentdiabetesinthechild.RiskwashighestinfirstbornchildrenanddecreasedprogressivelywithhigherbirthorderProfessorEdwinGaleandcolleaguesatSouthmeadHospitalinBristolsaid.Diabetesisaseriousincurablelifelongdiseasecharacterized以......作为特性byallinabilitytocontroltheamountofsugarintheblood.Insulin-dependentdiabeteswhichmainlyaffectschildrenistreatedbyadministeringthehormoneinsulin.Galelookedinto1375familiesintheOxfordareawhereoneormorechildrenhaddiabetesandfoundthattheriskofachilddevelopinginsulin-dependentdiabetesincreasedby25percentforeachfive-yearbandofthemothersage. Theriskofdevelopingdiabeteswasalsolinkedtotheageofthefather.Foreveryfive-yearbandofthefather’’sagetheriskofthechilddevelopingdiabetesincreasedbyninepercent.Theriskofdiabeteswashigh?estamongthefirstbornchildrenofmotherswhostartedtheirfamilieslateandtheriskdecreasedbyabout15percentforeachsubsequentchildtheBMJsaid.Theolderthemothertheearlierthestartofinsulin-dependentdiabetesinthechild.Otherstudieshavealreadyshownthatchildrenborntooldermothersovertheageof35haveanincreasedriskofdiabetesbutthisstudyisthefirsttoestablishthatriskincreasescontinuouslyinrelationtoincreasingmaternalageDr.PollyBingleyofSouthmeadHospitaltoldReuters路透社.Thenewstudyisthefirsttoshowthatriskisrelatedtobirthorder. Thestudyalsopartlyexplainsincreasingdiabetes.Between1970and1996theproportionofchildrenborntomothersagedbetween30and34increasedto28percentfrom15percentandthiscouldaccountforrisingnumbersofchildhooddiabetespatientsthescientistssaidinthealarmingincreaseintherateofinsulin-dependentdiabetesamongchildreninrecentyears.Thisstudymaywellprovideacluetotheunderstandingofthisproblem.ItismostlikelythatthereareanumberoffactorstoexplaintheincreaseDiabetesUKsaid.Therearesome1.4milliondiagnoseddiabetessufferersinBritainthecharityDiabetesUKsaid.Ofthese1.4millionsufferersthereare20000peopleunderage20whosufferfrominsulin-dependentdiabetes. AccordingtothepassagethealarmingincreaseintherateofdiabetesamongchildrenintheUKmaypartlybeexplainedbytherisein______.
MemoryClass StanFieldknowswhatagecandotoaperson’’smemoryandhe’’snottakinganychanceswithhis.Hechooseshisfoodcarefullyandgetsplentyofexercise.Healsoavoidsstresscocacolaandcigarettesmoke. What’’smoreatbreakfasteachmorningthe69-year-oldchemicalengineerswallowsaplatefulofpillsinthehopeofboostinghisbrainpower. MichelleAmoveislessthanhalfField’’sagebutnolessconcernedabouthermemory.Whileworkingroundtheclocktofinishadegreeinfilmstudiesthe33-year-oldNewYorkerhadthealarmingsensationthatshehadstoppedretaininganything.Icouldn’’tevenremembernamesshesays.IthoughtOhnoI’’mover30.It’’salldownhillfromhere.BesidesloadinguponsupplementsAmovesignedupforamemoryenhancingcourseatNewYork’’sMountSianiMedicalCenter.Andwhenshegotthereshefoundherselfsurroundedbypeoplewhowerejustasworriedasshewas. FormillionsofAmericansandespeciallyforbabyboomers生育高峰出生的人thedemandsoftheInformationAgeconflictwithasenseofdecliningphysicalpower.Whenboomerswereintheir30sand40stheylaunchedthefitnessboomsaysCynthiaGreenthepsychologistwhoteachesMountSinai’’smemoryclass.Nowwehavethemental-fitnessboomMemoryistheboomers’’newlife-crisisissue.Andofcourseamajormarketingopportunity.ThedemandforbooksandseminarshasneverbeengreatersaysJackLannomalongtimememorytrainerwhoseweeklyTVshowMindUnlimitedgoesoutto33millionhomesontheChristianNetwork.Anxiousconsumersarerushingtobuydo-it-yourselfprogramsandsupplementmakersaretryingtoselleverythingbutsawdust木屑asabrainbooster. Butbeforeyougetoutyourcheckbookafewquestionsareinorder.Doeseverydayforgetfulnesssignaldecliningbrainfunction?Ismegamemory超级记忆arealisticgoalfornormalpeople?Andifyoucouldhaveaperfectmemorywouldyoureallywantit?Untilrecentlynoonecouldaddressthoseissueswithmuchauthoritybutourknowledgeofmemoryisexploding.Newtechniquesarerevealinghowdifferentpartsofthebraininteracttopreservemeaningfulexperiences.Biologistsaretryingtounderstandtheunderlying潜在的chemicalprocessesandneuroscientists神经系统科学家arediscoveringhowagestressandotherfactorscandisruptthem.Nooneisclosetofindingthesecrettoperfectrecallbutasyou’’llseethatmaybejustaswell. Accordingtothewriterthesecrettoperfectmemory______.
Sulphurhas{{U}}occasionally{{/U}}beenfoundintheearthinanalmostpurestate.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. 21Interferoncauseshealthycellstogrow.
Weshouldbe{{U}}cautious{{/U}}incrossingacrowdedstreet.
EdwinHubble EdwinHubblechangedourideasabouttheuniverseandhowitdeveloped.Theworkoffewotherscientistschangedourunderstandingof【51】suddenly.Hemadehismostimportantdiscoveriesinthe1920s.Todayotherscientistscontinuetheworkhebeganbackthen.EdwinPowellHubblewasbornin1889inMarshfieldMissouri.He【52】hisearlyyearsinthestateofKentucky.ThenhemovedwithhisfamilytoChicagoIllinois.HeattendedtheUniversityofChicagotakingmathematicsandastronomy【53】hisspecialty. AsastudentHubblewasalsoamemberoftheUniversity’’sbasketballteamandanexcellentboxer.Severalpeopleurgedhim【54】fortheworldheavyweightboxingchampionshipaftercollege.Insteadhedecidedtocontinuehis【55】. InhisfirstobservationsfromMountWilsonCaliforniaHubbleusedatelescopewithone-hundredfifty-twoandbegan【56】moreandmoredistantobjects.Hisfirstgreatdiscoverywasmade【57】herecognizedaCepheidvariablestar.Cepheidvariablestarsarestarswhosebrightnesschangesatregularperiods. Hubblethenbegantoobservemoredetailsaboutgalaxies.Hestudiedtheirshapesandbrightness.By1925hehadmadeenoughobservationstosaythattheuniverseisorganizedintomanyshapesandsizes. Asstarsdifferfromoneanotherhesaid【58】galaxies.Accordingtohisobservationsthegalaxieshaveacenterandarmsofmatterthatseemtothecenterlikeapinwheel.Otherareshaped【59】baseballsoreggs.Afewhavenospecial【60】Hubbleproposedasystemtodescribegalaxiesbytheirshape.Hissystemisstillusedtoday.Healsoshowedthat【61】aresimilarinthekindsofbrightobjectstheycontain.Allgalaxies【62】arerelatedtoeachothermuchasmembersofafamilyarerelatedtoeachother. Inthelate1920sHubblestudiedthemovementofgalaxiesthroughspace.Hisinvestigationledtothemostimportant【63】discoveryofthe20thcentury—theexpandinguniverse. Hubbiesdiscovery【64】amajorchangeinourideasoftheuniverse.Theuniversehadnotbeenquietandunchangingsincethebeginningoftimeasmanypeoplehadthought.Itwasexpanding.Theexpandingoftenis【65】theBigBang.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. Theeffectinterferonhasoninfectionisthatitkeepshealthycellsfrombecominginfected.
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